Nebraska fans like to pretend to be a tier above Iowa so they act insulted when people call it a rivalry. For a lot of them it's not an act. Even though, as you said, we have many more BCS bowls, conference titles and top ten finishes over the past 15 years. Nebraska has none of these, zero.
It's all smoke and mirrors with them. For the life of me I don't know why a 4star from California would want to go to Lincoln. Actually I do know why and it's not tradition. btw, it's got to be downright humiliating for them to lose 40-10 in front of a captive national audience. They view that game as a big advertisement for Nebraska football.